LOS ANGELES  Soulful blues music emanated from an upstairs rehearsal room of the Los Angeles Theatre Centre, while rock n' roll poured from a downstairs auditorium.

The sounds were uncommon ones at the Theatre Centre, which generally presents non-musical classics and contemporary plays. But on a recent morning, rehearsals were underway for two musical shows: The Joni Mitchell Project, which opens today, and Blues in the Night, which opens Nov. 8.

The shows incorporate music from very different periods  the blues and jazz of the 1920s and 30s, and Mitchell's folksy songs from the 60s into the 90s. The productions are alike, though, in that they survey the landscape of human emotion.

The Joni Mitchell Project contains 24 of the songs that its namesake has written and recorded throughout her career. Among them are such hits as Help Me, Coyote, Both Sides Now, The Circle Game and You Turn Me On, I'm a Radio.

The songs are performed by three women and two men, who are backed by a five-person band.

The band rehearsed a fiery rendition of Mitchell's Dancin' Clown while David Schweizer, who is directing the project and is principally involved in its development, moved into a hallway for a chat.

"The five singers are travellers on a voyage of self-discovery  to clarify their love obsession and turn it into some kind of operable, adult thing that enhances their lives rather than ripping them apart," he explained.

Mitchell's songs are organized thematically, charting the characters' journey.

The characters experience youthful, crazy yearning; they become involved in messy, complicated relationships; and, ultimately, they see the light and move toward resolution.

"The emotions she's describing are complex," Schweizer said, explaining that the happier songs have an undercurrent of sadness, and the sadder songs have glimmers of happiness.

"She reflects the complexity of life's emotions  particularly romantically," Schweizer continued. "I think that's why people relate to her so strongly and have embraced her as a sort of emotional beacon. She's sort of like a reporter from the front; she's been through it and is telling about it in ways that people can relate to."

Not only do Mitchell's songs address a wide range of emotions, but they do so in a variety of musical styles.

"I think of them as contemporary art songs," Schweizer said. "She begins from the folk tradition, from the folk guitar structure. Modally, she has always continued to compose in that way. She's gone through many influences: a heavy jazz orientation at one point, a rock n' roll orientation at a certain point. She's explored whatever she's felt like exploring.

"But the kernel that has always remained is an intensely poetic and rather complicated use of lyric, and heightened musical structures to support the lyric structures.

"She's really a poet," he continued. "That word is tossed off casually whenever some writer can go a little further than love-above, moon-June. But what she says lyrically is incredibly interesting."

The show originated with Barry Krost, who is Mitchell's manager and a member of the Theatre Centre's board of trustees. He wondered whether some sort of show could be shaped from Mitchell's music. Schweizer, director of such inventive Theatre Centre productions as Kingfish, Demon Wine and The Illusion, was brought in to work on the project, and he, in turn, enlisted the help of Henry Edwards.

The creators hope to shape a theatrical piece that honors Mitchell's music, yet takes it where it has never been.

Schweizer observed that Mitchell has such a distinctive vocal style that when someone else performs them, they essentially become new songs.

Still, the show has Mitchell's unmistakable stamp.

The show has been developed with her approval, though she is not personally involved in it.

The show is in no way biographical, unless you consider that these songs must have come from a very personal place. "There is a level, of course, on which these five people are aspects and manifestations of her creative personality," Schweizer said.

Blues in the Night sings much the same song, but in a different key.

Its action unfolds during the course of a long, lonely night at a cheap hotel in Chicago in the late 1930s.

The characters are a blues singer who has fallen on hard times, a sophisticated woman who has made a career of her beauty and men's devotion to it, a girl from a small town who has fled to the big city after a ruined romance and a male saloon singer who comments on the women's predicaments.

"I hope what you see in the show is the full range of experience that any of us will go through on a lonely night, when we're feeling a little down," said Sheldon Epps, who conceived the show and is directing it.